1. Field
The present disclosure relates generally to aircraft and, in particular, to controlling the flight of an aircraft. Still more particularly, the present disclosure relates to a method and apparatus for controlling the flow of air using a plasma actuator.
2. Background
During flight, a pilot may use controls to adjust and control the movement of the aircraft. These controls may be used to manipulate the airflow over various parts of an aircraft. Control surfaces may control the flow of air over a surface of the aircraft where air flows. With control surfaces, the movement of an aircraft about different axes may be controlled. For example, the control surfaces may be used to control at least one of pitch, roll, and yaw for an aircraft.
Control surfaces may include, for example, without limitation, ailerons, elevators, rudders, horizontal stabilizers, vertical stabilizers, spoilers, flaps, slats, airbrakes, and other types of control surfaces. These types of mechanisms, however, may require maintenance and may not provide the amount of airflow control for a desired amount of performance. Further, these control surfaces may require movement of structures. The movement of these structures may include the use of actuators, hinges, and other structures to move a control surface.
One alternative to the currently used control surfaces may be a plasma actuator. A plasma actuator may control the flow of air over a surface through the formation of a plasma. This plasma also may be referred to as a dielectric barrier discharge. With a plasma actuator, a plasma may be formed between a pair of electrodes when an alternating current or nanosecond pulse voltage is applied across electrodes. Air molecules may be ionized in the vicinity of the electrodes and accelerated through an electric field. The plasma discharge may induce airflow, shock, and/or acoustic disturbances to change the flow of air over a surface.
Plasma actuators may provide for increased airfoil lift, separation delay, boundary layer transition, drag reduction, and other desirable features. Additionally, the use of plasma actuators may reduce and/or eliminate the need for control surfaces, such as ailerons or flaps. Plasma actuators may also increase the effectiveness of these control surfaces.
Currently available plasma actuators may not operate as desired or provide the desired amount of forcing under various pressures. As one example, currently available plasma actuators may become non-operational at unpredicted times. Additionally, currently available plasma actuators also may require more maintenance than desired.
Accordingly, it would be advantageous to have a method and apparatus which takes into account one or more of the issues discussed above, as well as possibly other issues.